Background: Syncope is a very frustrating chief complaint for many in the medical field. There is no gold standard test and no validated decision instrument. It represents about 3 – 5% of ED visits, 1 – 6% of hospital admissions, and in patients over the age of 65 years it is the 6th most common cause of hospitalization [2][3]. Additionally, both ED and inpatient work ups are notoriously low yield for finding significant pathology. Pulmonary embolism is one of the myriad of diagnoses included in the differential diagnosis of syncope, but there is little information looking at its prevalence amongst hospitalized patients. Fast forward to Oct. 20th, 2016 and there is now some evidence just published in the NEJM: The PESIT Trial.

Limitations:

A specific syncope workup was not mandated by all hospitals involved in the study

Imaging for PE was only performed in patients with an elevated D-Dimer and/or had a high pretest probability for PE

Confirmation of DVT in symptomatic patients was also not mandated

Search for other causes of syncope was left to the discretion of the physician, meaning other causes of syncope may have been under reported

No information was collected on treatment and follow-up of patients; therefore, we don’t know what the clinical outcomes of these patients was

Discussion:

Imaging to confirm PE was not done at admission, but up to 48 hours after admission. Immobility during hospitalization is a known to cause VTE

Authors conclusion of PE confirmation in approximately one in every six patients (17.3%) however these numbers are grossly inflated

2427 patients were actually included in this study (157 were excluded). Excluding all patients will overestimate the results, as was done in this study

97 patients had PE confirmed so instead of 97/230 (42.2%) the number should be 97/2427 (3.9%)

To take this one step further…if you exclude subsegmental PEs (i.e. Unclear clinical significance) the number is actually 80/2427 (3.2%)

Average Age of the patients in this study was 76 years

77.7% were ≥ 70 years

52.5% were ≥ 80 years

Although not studied would an age-adjusted D-Dimer [Age (years) x 10 ug/L for patients > 50 years of age] have reduced the number of tests performed

Many patients with confirmed PE were more likely to have previous VTE, Elevated RR, Tachycardia, Hypotension, clinical signs of DVT, and Active Cancer (i.e. Evidence of PE by History & Physical). In everyday practice any patient with evidence of PE would be worked up prior to admission. This further biases and overestimates the results of this study

Prevalence of PE in this study was 19% which is much higher than prevalence of PE in the US (i.e. 5 – 10%).

Author Conclusion: “Pulmonary embolism was identified in nearly one of every six patients hospitalized for a first episode of syncope.”

Clinical Take Home Point: Unfortunately, this study is a gross overestimation of PE, which may ultimately lead to over testing, without really knowing the clinical significance of identification as this was not truly studied.

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